Abstract:
The remediation of Cd (II) and Pb (II) was investigated by comparing two
nanocomposites, synthesized via two different carbothermal reduction routes, with
lignin biochar (Lig-BC) acting as the control. The two nanocomposites formed were
Lig-sG@nZVI and Lig-eG@nZVI. Lig-sG@nZVI was produced by depositing the
nanoscale zero-valent iron (nZVI) onto the surface of Lig-BC, whereas Lig eG@nZVI was formed by embedding the nZVI into the Lig-BC matrix itself. An
evaluation of the effect of pH and contact time for both metals was carried out. The
best-fitted model was the Sips isotherm for both Cd (II) and Pb (II). Maximum Sips
capacities for Cd (II) and Pb (II) were reported as 6.7, 9.7, 8.1 mg g-1
and 24.8, 35.7,
52.4 mg g-1
for Lig-BC, Lig-eG@nZVI and Lig-sG@nZVI respectively for both
metals. Regeneration studies were also carried out to explore the reproducibility of
the materials. A greater remediation was observed with Lig-eG@nZVI for CD(II) and
Lig- sG@nZVI for PB(II) respectively, and thereby it can be concluded that the
remediation of heavy metals can vary with different types of materials. Compared to
the control, both materials showed an enhanced performance, suggesting that nZVI
composites are a promising solution for heavy metal remediation.
